Threshold Scheme with Smart Card and Elliptic Curve Cryptosystem

以智慧卡實現門檻方法之橢圓曲線密碼系統

吳錫聰(Shyi-Tsong Wu) ； 邱炳樟(Bin-Chang Chieu)

《宜蘭技術學報》 9期電機資訊專輯 (2002/12) Pp. 1-10

https://doi.org/10.6179/nit.eec.2002.09.11

摘要

在非對稱的加碼系統中，橢圓曲線密碼系統以較小的金鑰長度達成相同的安全強度，因而日受重視，橢園曲線密碼系統的優點是其被廣泛應用於智慧卡、行動通訊之重要因素。本文應用橢圓曲線密碼系統以智慧卡來控制重要處所之門禁，如銀行金庫、實驗室等之門禁，基於一些安全考量，此重要門禁之控制須由其控制權限的一群成員來控制而非由單一成員所能控制，此涉及密秘分享之問題，解決之道乃應用所謂”門檻方法”每個合法成員持有一機密持份－存於智慧卡之次密鑰，經由特定個數之智慧卡上的次密鑰正確重建門禁控制的金鑰後，即可允許正常控制門禁。為防弊不誠實成員之不當門禁控制行為，欺騙者的偵測是必須要的機制。此外，智慧卡的密碼允許其使用者自由更改以方便使用者記憶，益顯本系統之人性化。

關鍵字

密碼學 ； 精圓曲線密碼系統 ； 智慧卡 ； 門檻方法

並列摘要

The application of Elliptic Curve Cryptosystem has gained more and more attention. ECC uses smaller key size and lower memory requirement to retain the security level and can be a crucial factor in the smart card system. An ECC based implementation of security schemes in smart card system to access coffers is proposed in this paper. For some specific safety consideration, access to coffers by a person is not permissive but a group of authorized people. It involves the problem of secret sharing. The adopted solution of sharing secret is threshold scheme. Every participant possesses a secret shadow, which will be saved in the smart card. After correct reconstructing the shared secrets, it is permissible to access the coffer's door. For resisting dishonest participants, cheating detection and cheater identification will be included. The user can change his password of smart card freely and need not to memorize his assigned lengthy password and shadow as traditional ID-based schemes makes our implementation much more user friendly.

並列關鍵字

Cryptography ； Elliptic curve cryptography ； Smart card ； Threshold scheme